﻿GLABEOUS MONTIPOR^. 35 



Specimen 6 is a portion of dead crust built up in the manner described. There are 

 small patches of the thin encrusting Montipora exigua upon it, which appears to differ con- 

 siderably from M, bolsii. It would thus appear that this hollow crust of explanate Montipores 

 is built up of three distinct species, of which M. holsii was, at the time of collection at least, 

 in the most vigorous growth, 



a. Billiton (with ilf. OTCoJispicMffl). Coll. Bolsius. [83.7.24.103.] (Type.) 



h. Billiton, a dead explanate coral crust „ „ 



(with Montipora exigua). 



18. Montipora erosa. 



Manopora erosa, Dana, Zoophytes (1848) p. 504, pi. 46, figs. 5, 5a. 



Non Montipora erosa, Quelch, Chal. Eep., Eeef Corals (1886) p. 178 (= M. solida). 



Description. — Corallum encrusting, but rising and expanding from a small base into 

 erect subangular branching stems which are "stout, acervately tuberculous, erose, obtuse," 

 contracting and enlarging irregularly. 



Calicles immersed, everywhere scattered, even at the summits. With a " flaring 

 aperture," the " star being situated rather deep within." One cycle of septa. 



The coenenchyma is not spinulous, but uneven and porous. 



The above somewhat obscure description is based upon Dana's text, and upon his figures 

 of a specimen collected by the United States Exploring Expedition from FijL There are no 

 specimens in the National Collection showing exactly the method of growth depicted. There 

 is, however, a fragment which shows some approach to this method of growth, and may be pro- 

 visionally placed here. The specimen had been provisionally labelled in Brltggemann's 

 writing M. Bus Forskal. But the original description of this latter species lays such stress 

 upon the presence of keels (" carinse ") and papillae that it is difficult to believe that it could 

 refer to a form like this specimen. This fragment bears some resemblance also to M. spongodes 

 (see p. 37). 



a. locality not recorded. [Eegister No. 97. 6. 18. 4.] 



19. Montipora solida. (PI. IV. fig. 1.) 

 Montipora erosa, Quelch (non Dana), Chal. Eep., Eeef Corals (1886) p. 178. 



Description. — GoraUum glomerate, swelling upwards from a comparatively small base 

 into great rounded (pulviuate) nodules, the smooth surface of which may be thrown into 

 irregularities owing to the presence of commensal Balanids. 



Calicles smaU (0*50 to 0-75 mm.), rather scattered, from 1 to 2 mm. apart. No clear 

 outline ; the aperture is conspicuous because generally sunk beneath the level of the surface 

 reticulum, through the irregular breaks in which the polyp must have protruded The septa., 



F 2 



